I've just reviewed the rack that i use this bag with (Topeak Explorer Bike Rack), and much of what i wrote there also applies to the bag, so i'll repeat a few things here (parts i've copied have an asterisk):
Just to start off, i should say that i am not really a 'hardcore' cyclist. If you're the kind of person who can put an entire bike together from memory, or the kind of person who commutes every day on a 900$ road bike and always wears spandex, your level of commitment and bicycle knowledge is probably years ahead of mine. I know enough to be able to name all the parts on my bike and do light maintenance, but i don't ride every single day, i don't tour, and i find road bikes kind of intimidating.*
That said, i like this bag a lot so far. The fabric and construction seem pretty high-quality and the whole thing feels very sturdy. There are reflecting stripes on the back for visibility, a weave of cord to hold irregularly shaped items on top of the bag, a shoulder strap, and a carrying handle. There is a mesh zip-up pocket on each side, the under-side of the lid has its own pocket, and then of course there's the large inner pocket. There are no built-in compartments, but the bag is roughly rectangular, so you could easily create your own.
As far as how the bag attaches to the rack (see link above): There is a 'foot' on the bottom of the bag that slides into the rails on the bike rack, which holds the bag down and prevents it from moving side to side. Then there is a clip on the front of the bag that clamps down on the bar at the front end of the rack, which keeps it from sliding off the back. It seems very secure and there is almost zero movement.*
My only complaint about the bag would be that it's not quite large enough to carry my purse or my netbook. But this is not really the bag's fault. Topeak make larger versions, including some with panniers, so i could have gone with them if i really wanted. But i'm cheap. :)Get more detail about
Topeak MTX Trunk Bag EX.
